Hiail John. Attached - photos of my Spitfire tail covered with silkspan, doped, painted with rattlecan automotive primer/filler,
blackline inked with marker pen using as little pressure as possible. Let ink dry/ cure overnight, Dusted with clear rattle can automotive to seal ink, wait a few minutes and slowly build up light coats till you are happy. Use back of wet n dry sand paper and wet sand - carefully - between coats to get a nice finish.
Cheers
John C